SPHENO-PALATINE GANGLION. 621 



The descending or palatine branches are distributed to the roof of the mouth, 

 the soft palate, tonsil, and lining membrane of the nose. They are almost a 

 direct continuation of the spheno-palatine branches of the superior maxillary 

 nerve, and are three in number : anterior, middle, and posterior. 



The anterior, or large palatine nerve, descends through the posterior palatine 

 canal, emerges upon the hard palate, at the posterior palatine foramen, and 

 passes forwards through a groove in the hard palate, nearly as far as the incisor 

 teeth. It supplies the gums, the mucous membrane and glands of the hard 

 palate, and communicates in front with the termination of the naso-palatine 

 nerve. While in the posterior palatine canal, it gives off inferior nasal branches, 

 which enter the nose through openings in the palate bone, and ramify over the 

 middle meatus, and the middle and inferior spongy bones ; and at its exit from 

 the canal, a palatine branch is distributed to both surfaces of the soft palate. 



The middle, or external palatine nerve, descends in the same canal as the 

 preceding, to the posterior palatine foramen, distributing branches to the uvula, 

 tonsil, and soft palate. It is occasionally wanting. 



The posterior, or small palatine nerve, descends with a small artery through 

 the small posterior palatine canal, emerging by a separate opening behind the 

 posterior palatine foramen. It supplies the Levator Palati and Azygos Uvulae* 

 muscles, the soft palate, tonsil, and uvula. 



The internal branches are distributed to the septum, and outer wall of the nasal 

 fossae. They are the superior nasal (anterior), and the naso-palatine. 



The superior nasal branches (anterior), four or five in number, enter the back 

 part of the nasal fossa by the spheno-palatine foramen. They supply the mucous 

 membrane covering the superior and middle spongy bones, and that lining the 

 posterior ethmoidal cells, a few being prolonged to the upper and back part of 

 the septum. 



The naso-palatine nerve (Cotunnius) enters the nasal fossa with the other 

 nasal nerves, and passes inwards across the roof of the nose, below the orifice 

 of the sphenoidal sinus, to reach the septum ; it then runs obliquely downwards 

 and forwards along the lower part of the septum, to the anterior palatine fora- 

 men, lying between the periosteum and mucous membrane. It descends to the 

 roof of the mouth by a distinct canal, which opens below in the anterior pala- 

 tine fossa ; the right nerve, also in a separate canal, being posterior to the left 

 one. In the mouth, they become united, supply the mucous membrane behind 

 the incisor teeth, and join with the anterior palatine nerve. The naso-palatine 

 nerve occasionally furnishes a few small filaments to the mucous membrane of 

 the septum. 



The posterior branches are the Vidian and pharyngeal (pterygo-palatine). 



The Vidian nerve, if traced from Meckel's ganglion, may be said to arise from 

 the back part of the spheno-palatine ganglion, and then passes through the 

 Yidian canal, enters the cartilage filling in the foramen lacerum basis cranii, 

 and divides into two branches, the large petrosal, and the carotid. In its course 

 along the Yidian canal, it distributes a few filaments to the lining membrane at 

 the back part of the roof of the nose and septum, and that covering the end of 

 the Eustachian tube. These are upper posterior nasal branches. 



The large petrosal branch (nervus petrosus superficialis major), enters the cra- 

 nium through the foramen lacerum basis cranii, having pierced the cartilaginous 

 substance which fills in this aperture. It runs beneath the Casserian ganglion 

 and dura rnater contained in a groove in the anterior surface of the petrous 

 portion of the temporal bone, enters the hiatus Fallopii, and, being continued 

 through it into the aquaeductus Fallopii, joins the gangliform enlargement on 

 the facial nerve. Properly speaking, this nerve passes from the facial to the 

 spheno-palatine ganglion, forming its motor root. 



The carotid branch is shorter, but larger than the petrosal, of a reddish-gray 

 color, and soft in texture. It crosses the foramen lacerum, surrounded by the 



